The present invention relates generally to programmable frequency dividers, and in particular to a programmable digital frequency divider and synthesizer which delivers signals at a frequency which is variable substantially linearly as a function of a set of input binary states.
With conventional programmable frequency synthesizers, which serve as a standard frequency source for motor speed control purposes, the output frequency is nonlinearly variable as a function of discrete variations of frequency control input signals. More specifically, the prior frequency synthesizer employs a programmable frequency divider whose output frequency is nonlinearly variable as a function of stepwise variations of the program control input signal. Therefore, as the ratio of frequency division is varied in response to the control signal the output frequency tends to deviate from the correct frequency and the amount of this deviation increases with increase in the output frequency.